Neural gain is the mechanism underlying the stability/flexibility trade-off, which is fundamental for goal-directed yet adaptive behavior. Inspired by the development of a computational model that...Show moreNeural gain is the mechanism underlying the stability/flexibility trade-off, which is fundamental for goal-directed yet adaptive behavior. Inspired by the development of a computational model that estimates gain, we assessed whether people rationally modulate gain to demands for stability and flexibility. We designed two task-switch digit-classification experiments with 60 participants each, in which we manipulated the proportion incongruency (PI) in experiment one and cue-to-stimulus interval (CSI) in experiment two. Our results indicated that PI manipulation did not significantly affect gain, yet incongruency costs and switch costs demonstrated an increase in stability in response to high PI. CSI manipulation significantly affected both gain and incongruency costs, demonstrating increased flexibility in response to a short preparation time. Furthermore, we used questionnaires to assess participants' ASD and ADHD trait scores and tested whether these predicted biases in gain and/or impairments in gain modulation. Despite the lack of conclusive findings, this study offers insight in the relation between ASD and ADHD and neural gain. More studies that overcome our limitations may discover the impairments in neurocognitive mechanisms underlying psychological disorders and inform treatment. Altogether, our results indicate that people rationally adapt to demands for stability and flexibility following an antagonistic trade-off. Therefore, this study contributes to the research on neuromodulation and adds to the general understanding of attention. Our findings may also help to inform applied research on the benefits and drawbacks of stability and flexibility in the workplace. Thereby, managers could be made aware of the number of tasks assigned to their employees and whether the demand to switch between them is proportional to their difficulty.Show less
Experimental research has repeatedly shown that the use of rewards can effectively promote cooperative behaviour in social groups. However, studies have only examined the effectiveness of rewards...Show moreExperimental research has repeatedly shown that the use of rewards can effectively promote cooperative behaviour in social groups. However, studies have only examined the effectiveness of rewards in uniform groups, and not whether rewards are effective in pluriform groups including people from different backgrounds. We investigate the effectiveness of rewards in promoting cooperation in pluriform groups in a social dilemma context. In a Public Goods game, we manipulate the ability of rewarders to distinguish in rewarding group members differently. We found that rewards were not effective when the rewarder could distinguish, which is not in line with our predictions based on the Bounded Generalized Reciprocity (BGR) theory and Social Identity Theory (SIT). The results suggest that people favour a fair allocation of rewards over reputational concerns. This has implications for the extent to which the SIT and BGR predict behaviour and how rewards should be implemented in real-world social dilemmas.Show less
Reorientation of attention is a fundamental part of human cognition. Spatial orientation is generally associated with dorsoparietal regions in the brain. Particularly, the posterior parietal cortex...Show moreReorientation of attention is a fundamental part of human cognition. Spatial orientation is generally associated with dorsoparietal regions in the brain. Particularly, the posterior parietal cortex, the lateral intraparietal cortex, and the right angular gyrus (AG) are assumed to mediate redirection of attention to behaviorally relevant stimuli. However, exact mechanisms and effect structures of reorienting to biologically significant stimuli have not been comprehensively identified. Time course and coordination in the dorsoparietal cortex remain unclear. Previous research has shown prioritized processing of emotional stimuli, particularly if threatening. Such affective processing is often associated with faster, subcortical activity. In the present study mediation by the right AG of reorienting to threat is examined. A spatial cueing paradigm was used and single pulse transcranial magnetic stimulation (TMS) was applied to the right AG at different stimulus onset synchronies (SOA) after target onset. Threat was introduced by means of differential fear conditioning of the targets stimulus. General linear mixed models with logit transform were used for analysis. TMS was predicted to interfere with reorienting (during invalid-cue trials) at an early SOA when threat is present. No such effects were observed. Rather, mediation by the right AG appeared to predominantly facilitate a correct response for contralateral targets. Further, TMS at 210 ms SOA improved performance for valid-cue conditions, independent of threat, suggesting that the right AG may act as inhibitory control. The discussed findings indicate a need for further investigation and suggested replication of more fundamental assumptions, such as direction of effects and lateralization of the AG.Show less
Trauma, cognitive flexibility, and empathy are widely studied constructs in psychology. However, inconsistent results are found regarding the aftermath of trauma. In the current study, it was...Show moreTrauma, cognitive flexibility, and empathy are widely studied constructs in psychology. However, inconsistent results are found regarding the aftermath of trauma. In the current study, it was expected that Syrian refugee children with higher severity of trauma symptoms scored significantly higher on cognitive flexibility and empathy tests than children with lower severity of trauma symptoms. To investigate these hypotheses, a quantitative cross-sectional study was conducted with a between-subjects design. The participants were asked to complete three questionnaires and two computer tasks to measure their cognitive flexibility, empathy, and trauma symptoms. Linear regression analyses showed that trauma was not a significant predictor of cognitive flexibility or empathy. If future studies could find this relationship in a larger sample, it possibly has implications for actively using cognitive flexibility and empathy as resilience factors during education for mental health professionals, therapeutic treatments of trauma, and in educational settings.Show less
Background. Stigmatization frequently occurs in individuals with a skin condition such as psoriasis, which can negatively influence their mental health and disease status. While stigma is known to...Show moreBackground. Stigmatization frequently occurs in individuals with a skin condition such as psoriasis, which can negatively influence their mental health and disease status. While stigma is known to be the leading cause of disability for these individuals, little is known about stigmatizing attitudes among the general population and its correlates. This study aimed to examine stigmatizing attitudes towards psoriasis among the Dutch population and investigated possible predictors. Methods. An online survey was administered to 124 participants, which were recruited based on convenience sampling. A 3 x 1 within-subject cross-sectional design was used, investigating the difference in stigmatizing attitudes towards the health conditions psoriasis and common cold (included due to COVID-19), and a healthy control condition. To describe the different conditions, vignettes were used. A one-way repeated measure Manova examined differences between the three conditions on stigmatizing attitudes (assessed by a social distance scale, a direct and indirect version of the impact of skin condition in daily life scale, stereotype endorsement scale, and emotion ratings). In addition, zero-order correlations and multiple regression analyses investigated possible predictors of stigmatizing attitudes towards psoriasis, including sociodemographic variables, familiarity and knowledge about psoriasis, indicators of the behavioral immune system and fear of corona. Results. Manova analysis displayed higher stigmatizing attitudes towards individuals with psoriasis as compared to the control group (p<.001). Besides, overall higher stigmatizing attitudes towards a common cold as compared to the psoriasis group were found. Higher stigmatizing attitudes towards psoriasis were correlated with lower knowledge, higher pathogen disgust, higher perceived infectability, male gender, and familiarity with psoriasis. No correlations were found regarding age, education, fear of corona, or gem aversion. Multiple regression displayed male gender, higher levels of pathogen disgust, and lower levels of knowledge about psoriasis to be predictors of stigmatizing attitudes (p<.05). Conclusion. Stigmatizing attitudes towards psoriasis is shown to be prevalent in Dutch society. As stigmatizing attitudes were shown to be related to reduced knowledge and male gender, future interventions might focus on these factors. Besides, different age groups and professions could be investigated in future studies. Further research is needed, as stigma towards psoriasis is rarely been investigated among the public.Show less
Posttraumatic Stress Disorder (PTSD) is a highly prevalent and debilitating disorder. The first line treatment for PTSD is prolonged exposure (PE) therapy. Inhibitory learning theory proposes...Show morePosttraumatic Stress Disorder (PTSD) is a highly prevalent and debilitating disorder. The first line treatment for PTSD is prolonged exposure (PE) therapy. Inhibitory learning theory proposes threat expectancy violation as a strategy to enhance effectiveness of PE. No standardized instrument for the assessment of threat expectancies is currently available. The aim of the current study was to assess the psychometric properties of the TREE, a novel instrument to assess threat expectancies. The reliability and factor structure of the TREE were assessed in a non-clinical sample of 158 trauma-exposed individuals. The TREE showed excellent reliability and was found to consist of four subscales: 1. Fear of dying/losing control, 2. Externalizing symptoms, 3. Negative evaluation, 4. Internalizing symptoms. The reliability of all subscales was good with an internal consistency ranging from .75 to .85. The TREE allows clinicians to tailor exposure sessions to the individual threat appraisal profile of their patients. Furthermore, by making threat expectancies explicit, it can aid in further understanding the mechanisms underlying PE. The factor structure of the TREE should be confirmed and its generalizability to the non-clinical and clinical population should be corroborated in future research.Show less
Background and aim: Although literature suggests that quality of life (QoL) in women with substance use disorders (SUDs) is lower than in men, it remains unknown whether this 1) applies to SUD...Show moreBackground and aim: Although literature suggests that quality of life (QoL) in women with substance use disorders (SUDs) is lower than in men, it remains unknown whether this 1) applies to SUD patients with psychiatric comorbidities in the Netherlands; and 2) whether there is a gender difference in QoL gain during treatment. This study therefore aimed to compare QoL (gain) between genders. Because research linked mood problems to worse QoL and substance usage in women, it was also the aim to compare genders in the association between (change in) mood problems and (change in) QoL. Methods: The longitudinal design involved data of day-patient treatments between 2018-2020. Sixty nine females and one hundred and thirty males with SUDs and comorbidities were assessed, using the EQ-5D-3L and the ICECAP-A. Analysis of variance and moderation analyses were performed with multiple imputation, controlling for treatment group. Results: At pretest, QoL in women was significantly lower when compared to men. There was no significant gender difference concerning gain in QoL, as well as regarding the association between mood problems and QoL at pretest and posttest. Conclusions: Women with SUDs and comorbidities experience lower QoL than men, a gender gap that is less profound in the normal population. Stigma and adverse life conditions arguably play a role. There is no evidence that men and women profit differently from treatment. In any case, mood problems, trauma experiences and meaningful activities could be considered more in future studies, as their association with QoL seems to be critical.Show less
Objectives: Some of the domains in which more experienced practitioners have been shown to outperform their less experienced colleagues relate to interpersonal skills, that can be measured by...Show moreObjectives: Some of the domains in which more experienced practitioners have been shown to outperform their less experienced colleagues relate to interpersonal skills, that can be measured by performance-based measure called Facilitative Interpersonal Skills (FIS). FIS has been identified as a strong predictor of treatment outcome, yet it is not known whether the FIS score is dependent on therapeutic experience. The present study tested the impact of clinical experience on FIS task performance by examining the influence of experience on FIS total score and the eight domains. Method: A total of 46 clinical psychology master’s students and 94 licensed cognitive-behavioural therapists participated in FIS assessment and provided information on their prior clinical experience. To test the hypotheses the multi-level growth model for repeated measures was employed. Results: Experienced therapists, on average, scored higher on FIS assessment than master’s students. The analyses of individual FIS domains revealed that the therapists performed significantly better on the 5 out of 8 FIS domains. Conclusions: Results were consistent with the hypothesis that the FIS assessment is dependent on one’s level of experience. The results imply that interpersonal skills can be modified through training or over the course of a therapeutic career. Conceptual and practical considerations of the findings are discussed.Show less
This paper explores the trajectory of amyloid accumulation onset in the brain relative to cognitive decline to potentially improve secondary prevention efforts of Alzheimer’s disease (AD). This was...Show moreThis paper explores the trajectory of amyloid accumulation onset in the brain relative to cognitive decline to potentially improve secondary prevention efforts of Alzheimer’s disease (AD). This was accomplished by attempting a replication of the study "Spatiotemporal distribution of β-amyloid in Alzheimer's disease is the result of heterogeneous carrying capacities" (Whittington et al., 2018) using data obtained from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database. Results showed that Whittington’s model of the temporal evolution of the in vivo PET β-amyloid signal over time (i.e. using the four parameters: the tracer nonspecific binding (NS), the exponential uninhibited growth rate (r), the time of half-maximal β -amyloid concentration (T50) and the carrying capacity (K)), and the derived “estimated time since disease onset” could be used to model β-amyloid accumulation trajectory. Additionally, by studying the relationship between the trajectory of amyloid accumulation and cognitive decline, the results showed that amyloid accumulation in the brain does precede cognitive decline and can be modeled to predict cognitive deterioration. Thus, it was concluded that “estimated time since disease onset” does serve as a possible effective predictive diagnostic tool of cognitive impairments and AD pathology. Additionally, this study emphasizes the need for future research on the mechanisms by which amyloid accumulation influences cognitive impairments.Show less
As inertia lacks a comprehensive definition, this thesis aids the formulation of a singular yet widely applicable definition. This is accomplished by examining the feasibility of definitions...Show moreAs inertia lacks a comprehensive definition, this thesis aids the formulation of a singular yet widely applicable definition. This is accomplished by examining the feasibility of definitions obtained through the scientific literature (a top-down approach) and laypeople (a bottom-up approach). A single definition for inertia proves to be elusive due to inertia’s many different uses, interpretations, and overlap with other constructs. For this reason, several distinguishing features were identified to differentiate inertia. In addition, a dichotomy between inertia as a behaviour and tendency was proposed to reconcile contradictions within the literature. Nevertheless, a classical definition with clear boundaries proved to be problematic. Therefore, a bottom-up approach examined through a prototype analysis whether inertia may have a prototype structure. In this case, inertia is best explained through many distinct, yet overlapping concepts instead of a few boundary conditions. In Study 1, participants freely generated features of financial decision-making. In Study 2, the resultant features were adapted to financial inertia and were tested for their representativeness. These preliminary analyses indicated that inertia might indeed have a prototype structure as numerous features were considered central to inertia. While these inferences are somewhat tentative until inertia’s prototype structure is fully confirmed in subsequent tests, there are indications that the dichotomy following from the top-down approach may mirror patterns in the most centrally rated features from the bottom-up approach.Show less
Social rejection is conceptualized as a threat to survival, yet the physiological mechanisms at work during social rejection have not received much attention. Prior research has shown a link...Show moreSocial rejection is conceptualized as a threat to survival, yet the physiological mechanisms at work during social rejection have not received much attention. Prior research has shown a link between heart rate changes and social rejection and the possible correlation of self-esteem levels to heart rate changes. Here we examined the effect of positive and negative peer feedback on heart rate changes of participants. Fifty participants (mean age = 20.4) took part in the newly developed social evaluation through feedback (SELF)- paradigm where they predicted, then received social evaluative feedback from four peers who differed in their probability of giving social acceptance versus rejection feedback. We hypothesized that social rejection would result in a transient slowing of heart rate and that this effect would be more prominent with unexpected social rejection. We also expected to find a significant difference in heart rate changes towards each different peer. Moreover, we expected self-esteem to influence heart rate reactions to feedback. As predicted, results revealed a more pronounced deceleration of heart rate during unexpected rejection, though this effect was also found with unexpected social acceptance. Difference in heart rate in response to feedback from each different peers was found, namely a transient slowing of heart rate for negative feedback from Peer 1 and positive feedback from Peer 4. Moreover, levels of self-esteem did not explain a significant amount of variance in heart rate changes. Future research should focus on a larger and more diverse sample size in order to confirm the current findings. This study added to current literature by again confirming a brake in heart rate during unexpected social rejection and by finding new results in heart rate during unexpected social acceptance from a more negative peer.Show less
Cut-off scores can be useful guides for researchers, clinicians or respondents in interpretating responses on psychometric instruments. Statistical methods involved in the development of cut-off...Show moreCut-off scores can be useful guides for researchers, clinicians or respondents in interpretating responses on psychometric instruments. Statistical methods involved in the development of cut-off scores are predominantly based on univariate analysis and in the presence of an observable criterion variable or normative sample data. To date, little is known about statistical procedures in defining multiple cutting scores for several latent variables within a multidimensional construct (i.e., subscales of a questionnaire). This study aims to evaluate the discriminatory power of various univariate and multivariate methods in cutting score development, and to explore a model-based clustering approach in setting cut-off scores for (sub)scales of multidimensional questionnaires. The investigated approach aims to cluster the responses on multidimensional constructs by using model-based clustering to classify respondents into ordered groups. Subsequently, cut-off points were identified as the intersection points of kernel density curves between the clusters or as (sub)scale split-rules in predicting cluster membership by the use of classification trees. A simulation study was conducted to compare the methods under medium and large sample sizes, various psychometric circumstances (the magnitude of factor correlations and item loadings), and across simulated homogenous and heterogeneous populations. Results of a simulation study show this model-based cluster approach is often preferred over percentile norms and linear standard scores in terms of discriminatory power, especially in defining two cut-off points. Recommendations for model selection and strategies to obtain cut-off points are given. Future research should focus to integrate the presented methodology into a case study using existing questionnaires to examine substantive implications of the calculated cutting scores. This study gives an overview the commonly known statistical techniques involved in cut-off score attainment, provides a multivariate framework to evaluate the discriminatory power in setting cutting scores, and lays out a promising novel application of model-based clustering in developing cut-off points for multidimensional questionnaires.Show less
Midfrontal EEG oscillations in the theta (4-8 Hz) band reflect a threat-detection mechanism, which might work differently in individuals with fear of negative evaluation (FNE) due to attentional...Show moreMidfrontal EEG oscillations in the theta (4-8 Hz) band reflect a threat-detection mechanism, which might work differently in individuals with fear of negative evaluation (FNE) due to attentional biases. This study aimed to examine FM theta reactivity to social-evaluation in a probabilistic feedback learning experiment, and possible biased learning processes in individuals with FNE, a hallmark feature in social anxiety. Additionally, the current study explored the possible mediating role of FM theta power in the relationship between FNE and emotion regulation. Fifty-nine undergraduate students (mean age = 20.5 years) participated in the newly developed SELF-profile paradigm. The participants received social rejection or acceptance feedback by (predominantly positive and negative) peers, which was either congruent or incongruent with prior expectations. Results revealed that unexpected peer feedback, regardless of the valence (acceptance or rejection), elicited a significant increase in FM theta power, as did feedback from the most negative peer. No association between FM theta power and FNE was found, and FM theta power did not mediate the relationship between FNE and emotion regulation (positive reappraisal or rumination). Behaviourally, participants had more difficulties in learning the probability of acceptance feedback for the negative peer than the positive peer. Individuals with FNE were slower in predicting acceptance feedback for the most positive peer, and felt more rejected after the experiment. Together, the results provided evidence that individuals with higher FNE seemed to display increased negative affect after receiving feedback and an attention bias towards threat. Furthermore, FM theta power seemed to reflect uncertainty-driven exploration.Show less
Background: Suicidal ideation is a grave symptom of major depressive disorder (MDD), that can have long-lasting cognitive effects. Cognitive Reactivity (CR) is the reactivation of depressogenic...Show moreBackground: Suicidal ideation is a grave symptom of major depressive disorder (MDD), that can have long-lasting cognitive effects. Cognitive Reactivity (CR) is the reactivation of depressogenic cognitions by dysphoric mood states, after recovery. CR is important as it predicts relapse. Previous studies found that individuals who have contemplated suicide may be particularly vulnerable to reactivation of depressive cognitions; however, suicidal ideation was assessed retrospectively. The present study is prospective. Methods: Cohort study. Participants who met the DSM-IV diagnostic criteria for MDD were included if they no longer satisfied the criteria two years later (N = 943). CR scores during remission were compared between individuals who were not suicidal during their index (baseline) episode (SI-) (N = 346), versus those who were (SI+) (N = 597) — within which, a subcategory of those who attempted suicide in their lifetime (N = 152) was included. Results: During remission, SI+ participants had significantly higher hopelessness reactivity scores than SI- participants, even when factoring current depressive symptoms and suicidality, and anxiety comorbidity. Current hopelessness reactivity was significantly predicted by previous suicidal ideation, and to a lesser degree, feelings of worthlessness/guilt. Participants who had attempted suicide had significantly higher aggression reactivity, compared to without a history of suicidality. Limitations: Cognitive reactivity may have been influenced by the unaccounted disparity in participants’ most recent suicide attempt, and the number of previous depressive episodes. Conclusions: The results support the differential activation model of suicidality. Robust and strong longitudinal associations are drawn between suicidal ideation during depression, and a subsequent, distinct cognitive reactivity profile on the hopelessness dimension during remission. Given the profile specificity of cognitive reactivity, preventative measures for relapse are promising. Further research including the number of previous depressive episodes, suicide attempts and their recency may strengthen the validity of findings.Show less
